<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    const arr =  [
  { 'id': '29', 'pid': '',     'name': '总裁办' },
  { 'id': '2c', 'pid': '',     'name': '财务部' },
  { 'id': '2d', 'pid': '2c', 'name': '财务核算部'},
  { 'id': '2f', 'pid': '2c', 'name': '薪资管理部'},
  { 'id': 'd2', 'pid': '',     'name': '技术部'},
  { 'id': 'd3', 'pid': 'd2', 'name': 'Java研发部'}
]
   function tranListToTreeList (arr){
    const map ={}
arr.forEach((item=>{
  if(!item.children){
    item.children=  []
  }
  map[item.id] = item
}))
// console.log(map);
const newarr = []
arr.forEach(item=>{
  const parent = map[item.pid]

  if(parent){
    parent.children.push(item)
  }else{
    newarr.push(item)
  }
})
return newarr
   }

// console.log(newarr);
// console.log(arr);
const res= tranListToTreeList(arr)
console.log(res);
  </script>
</body>
</html>
